1. Field of the Invention
The present invention relates to a processing equipment with a nozzle.
2. Description of the Related Art
A conventional processing equipment for a semiconductor wafer includes a chamber, an airflow generator for generating a downward airflow, a stage for mounting a semiconductor wafer, and a nozzle for supplying a photoresist to the semiconductor wafer.
The photoresist is supplied from the nozzle to the semiconductor wafer. The supplied photoresist is extended to the entire surface of the semiconductor wafer by rotating the semiconductor wafer. As a result, a photoresist layer is formed on the semiconductor wafer.
Since the semiconductor wafer is rotated, a part of the photoresist which is supplied on the semiconductor wafer flies off the semiconductor wafer as mist photoresist. The airflow generator generates the downward airflow in the chamber for making the mist of the photoresist flow downward.
However, during the photoresist supplying step, photoresist may remain on a supply port of the nozzle. The remaining photoresist may then become hardened by exposure to the airflow. The hardened photoresist may then fall on the semiconductor wafer. If the hardened phoresist falls on the semiconductor wafer, the photoresist layer may be formed non-uniformly on the semiconductor wafer.
To solve this problem, a technique has been known whereby the remaining photoresist is removed when the nozzle is not operated. Such technique is disclosed in Japanese Patent Laid-Open No. 2002-204992.
However, exposing the nozzle to the downward airflow increases the chances of hardening the photoresist. The hardened photoresist might fall on the semiconductor wafer, while the photoresist supplying process is performed.